This proposal represents an institutional response from the University of North Carolina at Chapel Hill (UNC) to become a Clinical Center under the RFA (DK-02-033) recently announced by the National Institutes of Health entitled: HEPATOTOXICITY CLINICAL RESEARCH NETWORK (HCRN). During year one, we will work with the Steering Committee to craft a standardized definition and, we believe, specific sub-definitions, of liver injury due to drugs, toxins, and complementary-alternative medicines (DILl). In addition, we will help develop and validate a diagnostic instrument for DILl. Year one will also be devoted to the development of protocols that will be HIPAA compliant, ethical, and have the highest likelihood for success in answering important questions concerning DILl. We propose a collaboration with researchers at the NIEHS that employs state-of-the-art technology to define the molecular events involved in acetaminophen toxicity. We also propose a second protocol that will define the natural history of DILl. The strengths of our proposal are: a) The location of our program within the UNC General Clinical Research Center (GCRC) which will allow efficiency through collaboration with existing GCRC personnel who have the demonstrated competence, experience, and infrastructure necessary for success. The GCRC will also serve as the centralized site for studies involving genotype/phenotype correlations, and we propose two such protocols, b) Cooperative understandings with the other two major academic medical centers in our region of the U.S. (Duke University and Medical College of Virginia), c) An extensive network of collaborating physicians, both gastroenterologists and primary care physicians, throughout the state facilitated by the UNC managed Area Health Education Centers (AHEC), d) Unique access to the state Medicaid database and evolving Emergency Department Network that will provide near real time access to HIPAA compliant patient data, e) Utilization of the traveling nurse team established by a co-investigator to enroll research subjects and to obtain biological specimens from anywhere within our state, f) Access to large banks of DNA that will facilitate gene association studies by providing controls, g) An investigative team that is lead by both a senior investigator who has extensive experience in both the clinical and research aspects of DILl and a junior investigator who has targeted DILl as the focus for a K23 award. The team has extensive experience in all aspects of multicenter clinical trials including data collection, regulatory issues, and productive collaboration across institutions. We anticipate that our proposed infrastructure will allow successful identification and enrollment of patients experiencing severe DILl within the mid-Atlantic region of the country.